[altq 1234] ALTQ conditioners on OpenBSD bridges

[Rémi Guyomarch <rguyom@pobox.com>]

Ok, I think I have a working code.

This little patch relative to OpenBSD 3.0 implements ALTQ conditioning
on bridged interfaces. Note that since all the hard work has been done
in the function sending IP frames to PF for filtering, I simply put
the ALTQ call just after the PF call.

This was tested with an NT4 box on one side of the bridge and a bunch
of NT and Unix servers on the other.

With this feature you can implement a transparent diffedge shaping and
filtering device, which is quite nice :) (no need to renumber or
adjust routes on your border routers)

Btw, I'm not by far an experienced kernel hacker. In fact it's the
first time I do kernel programming so I may have done something
terrible ;)

--- if_bridge.c 2001/08/21 15:18:20     1.76
+++ if_bridge.c 2001/12/07 22:58:14
@@ -1043,7 +1043,7 @@
                m_freem(m);
                return;
        }
-#if NPF > 0
+#if (NPF > 0) || defined(ALTQ)
        m = bridge_filter(sc, BRIDGE_IN, src_if, &eh, m);
        if (m == NULL)
                return;
@@ -1911,7 +1911,7 @@
        return (0);
 }
 
-#if NPF > 0
+#if (NPF > 0) || defined(ALTQ)
 /*
  * Filter IP packets by peeking into the ethernet frame.  This violates
  * the ISO model, but allows us to act as a IP filter at the data link
@@ -1926,9 +1926,6 @@
        struct ether_header *eh;
        struct mbuf *m;
 {
-#if NPF == 0
-       return (m);
-#else
        struct llc llc;
        int hassnap = 0;
        struct ip *ip;
@@ -2000,9 +1997,10 @@
 
        /* Finally, we get to filter the packet! */
        m->m_pkthdr.rcvif = ifp;
+#if NPF > 0
        if (pf_test(dir, ifp, &m) != PF_PASS)
                goto dropit;
-
+#endif
        /* Rebuild the IP header */
        if (m->m_len < hlen && ((m = m_pullup(m, hlen)) == NULL))
                return (NULL);
@@ -2015,6 +2013,16 @@
        ip->ip_sum = 0;
        ip->ip_sum = in_cksum(m, hlen);
 
+#ifdef ALTQ
+       if (altq_input != NULL && dir == BRIDGE_IN) {
+               if ((*altq_input)(m, AF_INET) == 0)
+                       /* packet is dropped by traffic conditioner */
+                       goto dropit;
+               ip->ip_sum = 0;
+               ip->ip_sum = in_cksum(m, hlen);
+       }
+#endif /* ALTQ */
+
        /* Reattach SNAP header */
        if (hassnap) {
                M_PREPEND(m, LLC_SNAPFRAMELEN, M_DONTWAIT);
@@ -2035,6 +2043,5 @@
        if (m != NULL)
                m_freem(m);
        return (NULL);
-#endif /* NPF == 0 */
 }
-#endif
+#endif /* NPF || ALTQ */ 


-- 
Rémi